Veritas Power Sharpening System - Primary / Micro-bevel Not Parallel

Never,

I don't think that this is true. As long as the blade holder holds the blade perfectly flat to the abrasive platter, how can the blade be ground out of square ?

Yes the outboard side of the blade does see a greater platter velocitiy, or as you put it: the blade sees extra paper. Agreed. But as long as the blade is held rigid, flat and in its original geometry relative to the platter, the entire length along the bevel must be ground uniformly.

Maybe, one way maybe to think of it is: even though the outer edge of the blade wants to be ground at a faster rate, the opposite end of the blade, the inner end (where grinding is going slower) is holding up the rest of the blade, up off the paper. So the entire bevel eventually gets ground down to the same level.

Now if the blade holder deforms, as I maintain, then you get crap.

Larry

Never Enough M> Even if the holder is perfect, how could you ever overcome the problem

Reply to
crane763
Loading thread data ...

Going off the edge of the platter is a good thing to try. I never did try that because the Veritas instructions explicitly say to stay away from the edge of the disk. If my patience returns, I'll give it a try.

Mark

Reply to
Mark Wells

I tried that with my jig, but didn't get exactly the same results. To do the test, I stacked 3 pieces of 1/4" glass. The legs of the jig were at "level 3" and the blade edge was at "level 1". (If I just put it on piece, then the clamping bar was in the way.)

I put a 2" plane blade on the left side of the jig. Then I tightened the left nut and made the right nut match. In that case, the right side of the blade (as viewed from the jig) was slightly up off the glass. As I tightened that nut tighter and tighter, it got worse. Ah ha!

Then I switched the blade over to the right side of the jig. I did the same experiment in reverse. Unexpectedly, the right side of the blade still didn't touch. I repeated both experiments a couple of times and got the same results. Maybe the blade is warped? They said in the instructions to look out for that.

Then I switched to a 1" chisel. No matter how hard I tried, I couldn't make a blade corner come up off the glass.

I don't know what the problem is, but it sounds like we agree that there is some kind of design flaw. This doesn't strike me as a production quality issue.

Mark

Reply to
Mark Wells

I spent some time experimenting this morning and I think I may have figured out what's going on.

First, I agree with Larry, as long as the blade is held parallel to the platter surface, the amount or speed of the abrasive passing under the blade should be of no practical consequence. Consider a worst case scenario; no abrasive at the center of the disk tapering to unused abrasive at the circumference. Even in this worst case, the difference in the amount of metal removed between the inside and outside edges of the blade, would be limited to the size of the abrasive particle. In the case of the 100 micron disk, this would be hard to measure. It certainly wouldn't account for the error that I and others on this group have observed. On the other hand, there is no question that Mark's observations are correct. The outside edge of the blade definitely gets ground down more than the inside edge, and by a rather significant amount.

As I gave this some thought, it occurred to me that the thickness of the platters may not be consistent. Sure enough, when I measured the thickness across the radius of the platters, I found that the outside edge is approximately .004 inches thicker than the remainder of the disk, probably as a result of a manufacturing operation. I verified this on three disks. I'm sure this is one of the reasons why Veritas recommends that you stay clear of the outside edge. My second thought was that the turntable that the platters rest on may not be perfectly flat. I checked this by installing a new (without abrasives) 4mm disk and then laying a precision straight edge across it. After accounting for the slight increase in platter thickness at the circumference, everything was dead flat, or at least within .001 inches. As I indicated in my original post, I was able to measure a slight bit of wobble at the outside edge as I rotated the platter, but this was consistent between platters at around .003 inches and shouldn't affect the bevel.

I next installed a new 100 micron disk on the 4mm platter and a new 9 micron disk on the 3mm platter. I used a spare 1 5/8? plane blade that I checked to make sure was both flat (no warp) and had parallel sides. I also ground the edge square to the sides and put an edge on it using conventional methods (water stones). I installed the blade in the holder and verified that it was absolutely square. I also checked to make sure that the edge remained flat after it was tightened into the holder.

I mounted the 100 micron disk and proceed to sharpen the blade, moving the holder back and forth along the guide bar, until a slight burr formed across the entire edge. When moving the holder, I remained approximately ½? from the center and outside edges. With the care I used setting everything up and the new media, I expected that I would initially see an edge that was pretty much square. It wasn't!

At this point I didn't know what to think, so out of frustration I once again put my straight edge across the platter, this time with the abrasive disks applied. I was really surprised to see a depression toward the center hold down. When I measured the disk without media, it was dead flat. I think what's happening, is that the rather thick cloth backing on the 80 grit paper is being compressed by the brass hold down and pulling the center of the platter with it. I measured the depression at around .004? which combined with the slight rise at the circumference, is more than enough to account for the error we're seeing. It also accounts for the micro-bevel not being parallel, because the thinner media on the 3mm platter doesn't result in the same problem, in other words, the 3mm platter remains flat.

Your thoughts?

Reply to
woodworker1000

SNIP

I'm really not sure that I follow what you're saying here. But I'll take a close look at my setup to see if my platters also get depressed toward the center. I don't remember actually looking at the flatness of the installed platter. But I did set up the support bar so that it was parallel to the side of the platter that I was grinding on. If all the platters depress the same amount, then referencing the support bar relative to the left side of the platter, say, would account for the un-flatness, well enough. If all the platters depresss different amounts, then this wouldn't work.

I don't undertstand how the grade of abrasive makes any difference in how much the platters are depressed toward the center. ?

Oh, Mr Lee.....Are you out there? Any chance you can get your designers to think about this?

Larry

Reply to
crane763

Mark, When you switched the blade to the right side and tightened up, did maybe one of the legs come up off the glass, rather than the blade. I found this to happen, that the blade was still sitting flat, but the holder had deformed and one of the legs was now off the table and you could rock the entire blade/holder.

That's odd. I found that the narrower the blade, the easier it was for me to get the blade/holder to deform. However, because the blade was narrower, it was harder to see: the absolute amount that the blade corner lifted up off the table was less. (am I explaining that clearly?)

Larry

Reply to
crane763

It sounds logical, but as I picture it, the one corner wears faster, and to hold it rigid you have to do so without the edge near the center. This seem unstable like a 4-legged chair with one leg shorter than the others.

Reply to
Bruce Barnett

Reply to
Never Enough Money

Yes, I understand. I went out and conducted the test again. This time I used a 3/4" chisel and a block plane blade. I paid more attention to the legs. I couldn't get the jig to deform with the chisel using the methods of measure I had. With the block plane blade, I was able to get the jig to deform, but only if I really, really pushed it.

Normally to tighten blades in the jig, I would tighten the nut closest to the blade and then make the other nut match by looking at the threads on the post. Then I would turn the jig over and make sure the clamping bar was not obviously deformed. Using that technique, the blade seems to be secure and the jig not deformed (at least for me!).

I'll have to lookup when I bought my machine. It was several years ago, so it is possible that Larry and I have different jigs. The top bar (attached to the legs) on my jig is pretty beefy. It is significantly thicker than the clamping bar. The clamping bar is easy to deform, but I don't think deformation of the clamping bar alone impacts the performance of the jig.

On the issue of disk flatness, my 80x disk is flat as far as I can tell. With a straight edge across it in several different chords near the center, I can't get a 0.003" feeler gauge under it. I also can't see light under the straight edge. I turned the machine on and it looks like it is spinning perfectly flat to me. The disk does wobble slightly laterally, but it's not much and I don't see how that could matter, anyway.

On the issue of grinding at different rates against the inboard and outboard edges of the blade, I still think that might be an issue. The experience of woodworker1 and myself seem to corraborate that. I agree that if the blade were completely rigid that the rotational speed wouldn't matter. However, the blade is not rigid, so let me start speculating: As you grind away material, the blade moves, ever so slightly, back toward the bar. Furthermore, the operator is applying pressure to the blade. I know from my hand sharpening that a plane blade will deform relatively easily under pressure. In hand sharpening, I use that to my advantage by putting pressure where I need more honing. That compensates for slight misalignments in the jig. It seems like blade and/or jig deformation could happen as the operator applies pressure, which would allow the faster moving abrasive to take off more material.

Think about it this way: The operator starts grinding. The outboard side of the blade gets ground a little more quickly and gets very, very slightly shorter than the inboard side. The operator's pressure then causes the outboard side to again be next to the disk by very slightly deforming the blade, jig, bar, or some combination. This process continues until you reach a limit in which the deformation wouldn't happen any more. Now the operator picks up the blade and the edge is not square to the side of the blade.

Maybe try very light pressure? In the past, I have tried only holding the jig and just applying force to the jig against the bar and not near the edge of the blade. That seemed to help slightly, but not significantly.

For the poor sap who finds all this on Google ten years from now, here's a summary of the problem again: With the Veritas Mk. II Powered Sharpening System, blades are not ground perpendicular to the edge. This is usually first noticed when the primary and secondary bevels are not parallel to each other, but can also be seen if you put a square up to the edge after grinding. This is not a cosmetic issue. The edge can easily be out of square enough to impact performance of the blade and/or make it very difficult to grind a secondary bevel all the way across the edge.

Mark

Reply to
Mark Wells

snipped-for-privacy@hotmail.com wrote: [snip]

What you are describing is exactly what I have experienced. Careful setup, etc. and the edge is not square.

Mark

Reply to
Mark Wells

This may be a stupid question, but if the setup consistently makes the blade out of square then why can't you just set up the jig slightly out of square to compensate?

-Leuf

Reply to
Leuf

I have a hard time imagining that nut compressing the backing to create an even angle all the way out to the edge of the platter, but the easy way to test would be to enlarge the center hole to the same size as the nut so that it bears on the platter not the paper. If that's the problem then it's an easy fix.

-Leuf

Reply to
Leuf

Yes, exactly. As long as someone or something (the tool/blade holder) firmly holds the chair in its original orientation with the 3 longer legs in contact with the ground, the one shorter leg cannot contact the ground until the 3 longer legs are all equally shortened or ground down.

Reply to
crane763

No, the tool holder must be a constant distance across the highest point of the paper or stone. The Makita directions I mentioned refer to it when they say take the edge off the stone and cut uphill by tilting the rest. Where you've ground already needn't be a drag on the stone or grit, you're done with it, and would rather it grabbed air.

The obsession with flat abrasives and holders is nice, but if you pass the blade across a 1/16 wide jeweler's blade at a consistent distance, you'd get a straight edge. Don't take the work away from the holder by pressing into the stone, that's honing. This is still grinding.

Reply to
George

That is what I try to do: count threads or use a caliper to make sure the gap between the top of the tool holder and the clamping bar is equal on both sides. I find that if the face and back of the blade are co-planar (like a plane iron) then I don't need that much clamp pressure to hold it still. If I try to clamp up a chisel that has some angle, however slight, between the face and back surfaces, then there is no way I have been able to clamp it up, so that it doesn't move, without deforming the holder. I've even tried a strip of the self-adhesive high friction tape on the tool holder, but it just squishes away to nothing. I guess the point, which you have already made repeatedly, is that one shouldn't have to go through all this fussing to simply grind a square edge on a blade with a $350

*sharpening system*.

I got my machine about 6 months ago. It is beefy-Not.

I agree. It doesn't matter that the clamp bar bends.

This could indeed happen, that finger pressure near the gringing edge slightly rocks the blade, forcing it to go out of flat relative to the platter. Maybe when I have an afternoon to totally flush down the toilet I will experiment once again. However, I was, just like you, mindful of this possibility and believe that I purposely did not apply pressure to the blade near the grinding edge. I very patiently let the abrasive do its work, applying minimum pressure nearer the holder and main bar. Again, if the holder is deforming given my method of operation, then this just reinforces my main gripe - that the tool holder is too flimsy and needs to be re-designed.

I was thinking that it wouldn't be horrible to have two or several types of holder. A universal design would be nice, but it doesn't have to be so. For parallel sided blades, either plane irons or chisels, a side clamping mechanism would be best. It would solve the two main issues: 1. It would be self squaring. 2. You would need much less force to hold the blade still.

Reply to
crane763

Yes. I agree. I like the example of the very narrow abrasive. Still, the tool-holder/blade/abrasive geometry must remain constant throughout the grinding operation. The blade can be slid side to side, as when you use a narrow belt sander, but the tool-holder must not deform.

Reply to
crane763

Not stupid at all. I had just about gotten to this, when I ran out of steam and soured on the whole thing. I'm not sure that the out of squareness is consistent enough to compensate simply by skewing the jig bar. (I still think flexing of the holder is the issue) Still, I bet you could get much closer to accceptability.

Reply to
crane763

On Dec 6, 5:41 am, "George" wrote: [snip] No, the tool holder must be a constant distance across the highest point of

Doesn't that mean "flat" -- flat with respect to the paper?

Reply to
Never Enough Money

Excellent summation Mark. Now at least there is something on the Web regarding this issue. When I posted my initial message, I couldn't find a single mention of the problem. Maybe someone from Veritas will read it and come up with a permanent solution. Stop to think of it, maybe I'll just forward the Google link to them for comment.

According to their web site, Lee Valley will be at the Milwaukee woodworking show in February. I live in Chicago, which is only 80 miles away, so I may just pack up the sharpener along with my sacrificial plane blade and haul it up there. If they can't make it work either, and I'm confident they won't, they might be more inclined to address the problem. It's been my experience that both Lee Valley and Veritas have a genuine concern about quality and once they're convinced that a problem really exists, they do something about it.

Reply to
woodworker1000

I just got the Veritas system. In trying to sharpen a plane iron, I can't seem to get an edge which is square to the sides of the iron. I just found this thread while googling for solutions to the problem.

I should admit now that I'm a newbie when it comes to hand planes. I'm trying to learn. I've got Garret Hack's book and Lee's book and I've watched two of Charlesworth's videos.

Anyway, here's my question: If the edge is very slightly out of square, how big of a problem is it? Is it possible to even use a plane which has a blade that is sharpened very slightly out of square?

In my latest attempt to use the Veritas, the result looks pretty good. It's not square, but it's awfully close. With a precision square, I can barely see light coming through at one side of the sharpened edge.

But when I put the blade into the plane (a Record #4) and try to take a shaving, only one side of the blade cuts at all.

I am of course still going to try and figure out how to get a square edge, but I'm guessing the squareness of the edge is not my only problem. The results I'm seeing make me think that my real problem is in the setup of the plane.

So I'm looking for any advice from those with more experience. I'm sort of anticipating one of two responses:

  1. Yes, Eric, you're probably doing something wrong in the setup of the plane. A plane iron with a slightly out of square edge can basically be used, even though it's not optimal. Go study more of the beginner-oriented plane stuff.

  1. Sorry Eric, actually the edge on the plane iron has to be perfectly square. The tiniest error will basically render the plane unusable in the manner you describe.

Thanks in advance!

Eric Sink

Reply to
eric

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.